Band Tensioning Tool Insert

ABSTRACT

A band tensioning tool is provided that employs a replaceable insert juxtaposed to a tensioning wheel. The insert is made of low-friction material wherein band galling and tension wheel slippage is drastically reduced. The tool employing the contemplated insert can tension bands of various material properties with predictable repeatability.

This application claims the benefit of U.S. Provisional Application Ser.No. 61/682,014, filed Aug. 10, 2012, the entire disclosure of which isincorporated by reference herein.

FIELD OF THE INVENTION

Embodiments of the present invention are generally related to bandtensioning tools. More particularly, one embodiment is a tool with aninsert positioned beneath, and spaced from, a tension wheel thatfacilitates band tensioning and reduces tool malfunctions.

BACKGROUND OF THE INVENTION

Corrosion-resistant metallic bands are used in oil drilling operationswhere exposure to seawater, chemicals, drilling fluids, etc. is common.Carbon steel bands have been used in these applications and have beensuccessfully tensioned by existing tensioning tools, such as Fromm'sA480 tool. Zeron, a stainless steel with excellent corrosion resistanceand high strength characteristics, is also commonly used. Nickel alloysare also used, such as Inconel and Monel, which are corrosion and heatresistant. The problem of using stainless steel or nickel alloy bands isthe existing band tools provide inadequate tension and the tensionprovided varies from band-to-band.

FIGS. 1-4 show the Fromm A480 tool 2. The tool employs apneumatically-driven knurled tension wheel 6 that is spaced from areplaceable insert 10 located in a breaker foot 14. A spring biases thetension wheel 6 towards the breaker foot 14. A lever 18 is used toseparate the tension wheel 6 from the breaker foot 14, which allows aband to be inserted therebetween. The operator releases the lever 18 andpneumatic pressure is used to rotate the tension wheel 6 which tensionsthe band. That is, as the tension wheel 6 rotates, the band is pulledacross the insert 10, thereby tensioning the band about an object(s). Auser-controlled “pressure setting” of the tool 2 is proportional to theamount of pressure applied by the tension wheel 6 onto the band, thelevel of band cutting force available, and band pull speed.

When a desired band tension is achieved, the tension wheel 6 will stallor repeatedly slip at the point of band contact because the pneumaticpressure used to rotate the tension wheel 6 will be insufficient toovercome the tension exerted by the band (i.e., a force in a directionopposite from the band pull direction). When the tension wheel 6 stalls,the operator surmises that the proper band tension has been achieved anduses lock forming jaws of the tool 2 to deform a buckle or seal aboutthe band. After the band has been locked, the excess portion of the bandis severed therefrom by a pneumatically driven knife/blade mechanism ofthe tool. If the tension wheel 6 slips before the desired band tensionis achieved, because of increased friction between the band and insert,or because the tension wheel is rendered ineffective, the operator willmistakenly believe the desired tension has been reached and will lockand cut the band prematurely.

Again, existing tools tension carbon steel bands effectively, but bandsmade out of stainless steel, for example, often pose problems. Forinstance, compression of stainless steel bands against existing insertscause the band and/or insert to gall as the band moves relative to theinsert. Galling can occur after a small number of bands are tensioned.Galling, i.e., adhesive wear of the tension wheel or the insert,adversely affects tool performance because it can cause material to beremoved from the band which can clog spaces in the knurled surface ofthe tension wheel. As one of skill will appreciate, altering the tensionwheel in this fashion causes slippage and, thus, ineffective tensioning.Tension wheel slipping also causes the tension wheel to wearprematurely. Further, galling often alters the shape of the band, whichmay render adding additional band seals to a severed end of a band coildifficult.

Galling is addressed in some ways by coating the band with wax, whichadds cost and complexity to band manufacturing. Alternatively, tooloperators choose to accept some level of galling and compensate forslipping by modifying the pressure setting to increase the pressure thetension wheel applies on the band. Regardless of the techniques used toaddress the slippage, studies have shown that a given number ofstainless steel bands tensioned with an existing tool often deviate inband tension performance, which indicates inconsistent and unpredictabletool performance.

Another way to address galling is to employ a pinch wheel opposite thetension wheel, which is disclosed in U.S. Pat. No. 6,073,664, theentirety of which is incorporated herein. Changing existing tools toincorporate a pinch wheel would require major modifications.

Thus is a long felt need to provide a band clamping tool that providesaccurate and repeatable tension from band to band. It is also desirableto provide a band tensioning tool that prevents or reduces the amount ofslippage between the pinch wheel and the band and, thus, prolongs lifeof the tension wheel.

SUMMARY OF THE INVENTION

It is one aspect of embodiments of the present invention to provide atool that addresses galling and performance issues commonly experiencedby existing band tensioning tools. More specifically, one embodiment ofthe present invention employs a low-friction insert that works inconjunction with a tensioning wheel. The contemplated insert has a roomtemperature tensile strength between about 20,000 to 32,000 psi, roomtemperature tensile modulus of between about 3-4 Mpsi, room temperatureflexural strength of between about 30,000 to 50,000 psi, roomtemperature flexural modulus of between about 4.9 to 4.12 Mpsi, roomtemperature compressive strength of between about 40,000-75,000 psi, androom temperature coefficient of friction of between about 0.15 to 0.20.In one embodiment of the present invention, Wearcomp® manufactured byHycomp® was used, but one of skill in the art will appreciate that anymaterial that meets these or similar material properties may be usedwithout departing from the scope of the invention. Wearcomp® iscomprised primarily of pmr-15 polyamide resin (40%-60%) and carbon fiberor graphite (40%-60%).

The contemplated low-friction insert is placed within a foot of the tooland is spaced from the tension wheel. In operation, a band is compressedbetween the tension wheel and the insert. When the tension wheel isrotated and the band tensioned, the low-friction insert allows the bandto slide without galling, which increases tension wheel effectivity. Asa result, the insert allows for increased tension wheel pressure to beapplied, which influences band tension and pull speed.

It is one aspect of embodiments of the present invention to provide aband tensioning tool comprising: a pneumatically-powered tension wheel;a foot spaced from the tension wheel, the foot having a recess; a leverassociated with the foot that selectively moves the foot away from thetension wheel; and an insert positioned in the insert, the recess beingmade of a low-friction material.

It is yet another aspect of embodiments of the present invention toprovide a band tensioning tool comprising a gear housing having atension wheel protruding from a portion thereof; a foot pivotallycoupled to the gear housing and having a band support portion disposedgenerally opposite the tension wheel; a compression foot spring having afirst end portion associated with the gear housing and a second endportion associated with the foot, the compression foot spring adapted topivotally bias the band support portion of the foot toward the tensionwheel; a handle having a first end portion coupled to the foot, thehandle having an intermediate portion and a second end portion extendingfrom the foot generally along the axial dimension of the gear housing,the handle being actuatable toward and away from the gear housing topivot the foot against the pivotal bias of the compression foot spring,which moves the band support portion away from the tension wheel toprovide a band-receiving gap, the improvement comprising: a low-frictioninsert incorporated in the foot, the low-friction insert being generallyaligned with, but spaced from, the tension wheel when the handle isactuated toward the gear housing.

It is still yet another aspect of embodiments of the present inventionto provide a method of securing a band about a plurality of objects,comprising: providing a band tensioning tool comprising apneumatically-powered tension wheel, a foot spaced from the tensionwheel, the foot having a recess, a lever associated with the foot thatselectively moves the foot away from the tension wheel, and an insertpositioned in the insert, the recess being made of a low-frictionmaterial; moving the lever to separate the foot from the tension wheel;placing a band between the tension wheel and the foot; releasing thelever which moves the insert into engagement with the band, the bandalso being engaged to the tension wheel; rotating the tension wheel,which moves the band across the insert; achieving a predetermined bandtension; deforming a seal about the band to create a band loop; andsevering an excess portion of the band.

The Summary of the Invention is neither intended nor should it beconstrued as being representative of the full extent and scope of thepresent invention. Moreover, references made herein to “the presentinvention” or aspects thereof should be understood to mean certainembodiments of the present invention and should not necessarily beconstrued as limiting all embodiments to a particular description. Thepresent invention is set forth in various levels of detail in theSummary of the Invention as well as in the attached drawings and theDetailed Description of the Invention and no limitation as to the scopeof the present invention is intended by either the inclusion ornon-inclusion of elements, components, etc. in this Summary of theInvention. Additional aspects of the present invention will become morereadily apparent from the Detail Description, particularly when takentogether with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the invention andtogether with the general description of the invention given above andthe detailed description of the drawings given below, serve to explainthe principles of these inventions.

FIG. 1 is a perspective view showing a band tensioning tool of the priorart;

FIG. 2 is a front elevation view of FIG. 1;

FIG. 3 is a detailed view of FIG. 1 showing the bottom portion of thetool;

FIG. 4 is a detailed view of FIG. 1 showing a tension wheel spaced froman insert;

FIG. 5A is a perspective view of an insert employed by one embodiment ofthe present invention;

FIG. 5B is a front elevation view of FIG. 5A;

FIG. 5C is a side elevation view of FIG. 5A;

FIG. 6 is a table showing retained force of bands of various materialcompositions tensioned with a tool of one embodiment of the presentinvention;

FIG. 7 is a table showing loop tensile force achieved by bands tensionedwith tools of one embodiment of the present invention;

FIG. 8 is a table showing band pull speed provided by one embodiment ofthe present invention;

FIG. 9 is a table comparing steel inserts with inserts employed by someembodiments of the present invention;

FIG. 10A is a perspective view of a tool showing removal of side coverscrews;

FIG. 10B is a perspective view of a tool showing removal of the toolside cover;

FIG. 10C is a perspective view of a tool showing removal of a tensionwheel;

FIG. 10D is a perspective view of a tool showing removal of an existinginsert or the replacement of a low-friction insert; and

FIG. 10E shows the installation of the replacement insert into a foot.

It should be understood that the drawings are not necessarily to scale.In certain instances, details that are not necessary for anunderstanding of the invention or that render other details difficult toperceive may have been omitted. It should be understood, of course, thatthe invention is not necessarily limited to the particular embodimentsillustrated herein.

DETAILED DESCRIPTION

As briefly described above, FIGS. 1-4 show a band tensioning tool 2commonly used in the industry to tension a band claim. The tool 2includes pneumatically-driven tension wheel 6 that is spaced from a foot14 that accommodates a low-friction insert 10. In operation, the usermoves a lever 18 that moves the foot 14 away from the tension wheel 6,which allows a band to be placed therebetween. When the lever isreleased, the band is compressed between the low-friction insert 10 andthe tension wheel 6. A pneumatic motor is initiated to rotate thetension wheel to tension the band. After a predetermined tension isachieved, a locking mechanism is employed that deforms a portion of aseal about the band, which maintains the applied tension, and the excessband portion, which extends beyond the seal, is severed. The componentsand functionality of existing tools is described in U.S. Pat. No.4,380,255, which is incorporated by reference herein, and thepreviously-mentioned U.S. Pat. No. 6,073,644. The contemplatedlow-friction insert may be incorporated into these, or similar, tools.The Locking a seal by crimping is described in U.S. Pat. No. 7,484,274,which is incorporated by reference herein.

FIGS. 5A-5C shows a low-friction insert of one embodiment of the presentinvention. Although the shape of this insert is circular, one of skillin the art will appreciate that the insert may have any shape so long itcan be accommodated in a cavity provided in the foot. The insert mayalso include a cavity that receives a secondary insert that is removabletherefrom.

FIG. 6 is a table showing retained force of bands that were tensionedusing a stock Fromm tool versus those using a Fromm tool employing thecontemplated low-friction insert. Here, bands made of Zeron, Alloy 400,304 stainless steel (one quarter hard), and 316 stainless steel weretensioned. A retained force (i.e., the force exerted on the objects bythe band) of about 500 pounds was achieved when a Zeron band wastensioned with a stock Fromm tool and a retained force of about 280pounds achieved by a tool using a tool with a low-friction insert. Whentensioning an alloy 400 band, the stock tool produced a retained forceof about 150 pounds compared to a retained force of about 250 poundsachieved by a tool with a low friction insert. In the case of a 304stainless steel (one-quarter hard) band, the retained force was 550pounds using the stock tool and about 340 pounds when using a tool witha low friction insert. Finally, when a 316 stainless steel band wastensioned using a stock tool, 90 pounds of retained force was attainedcompared to about 210 pounds using the low friction insert. Accordingly,one of skill in the art will appreciate that a tool employing alow-friction insert provides a more predictable and consistent bandclamp performance over a wide range of materials compared to the stocktool.

These test results illustrate band performance repeatability, which isimportant, as users will often use bands of different materials fordifferent applications. In the past, the band material would dictate theamount tension applied wherein the user would have to modify toolparameters to achieve the desired tension. Embodiments of the presentinvention address this issue by providing an insert that tensions bandsof different materials to the same level degree, thereby increasingrepeatability and reliability. For example, bands made of Zeron, Alloy400, 304 stainless steel, and 316 stainless achieve a retained force ofat least about 200 psi. The table shows that the retained force of bandsapplied by the stock Fromm tool varies depending on band material.Repeatability is often the driving force in banding operations, becauseit allows users to be confident that the tension applied to each bandmeets a predefined design criteria.

FIG. 7 shows that a tool employing a low-friction insert clamp strengthwill be unchanged over a wide range of pressure settings. Morespecifically, the loop tensile force provided by a band tensioned with atool employing a low friction insert is about 3,500 lbf regardless ofthe tool pressure, i.e., pressure the tension wheel imparts on the bandand insert, which is comparable to the tool loop tensile force providedby band tensioned with the stock tool. Thus using a low-friction insertdoes not adversely affect loop tensile performance.

FIG. 8 shows bands may be tension much faster when using a low frictioninsert. More specifically, tools using a low-friction insert are capableof operating at lower torque because excess power is not needed tocounteract friction associated with the band moving across the insert.Such tools are desirable as they can pull band at higher speeds whileapplying the desired tension and while providing sufficient pneumaticpressure to sever bands of various materials. Employing a low-frictioninsert, the pull speed may be doubled because a high speed motor may beused. Conversely, prior art tools cannot use a high speed motor becauseof the detrimental effects of tension wheel slipping and/or galling,which affects the applied tension and which can stall the tool. Here, atool employing a low-friction insert has a band speed rate of about 7in./s wherein the prior art insert allows for a band pull speed of about3.2 in./s (because a low-speed transmission is commonly used). As one ofskill in the art will appreciate, pull speed is directly related to theamount of bands that can be installed in a given amount of time.

Referring now to FIG. 9, Zeron and Alloy 400 (full hard) bands weretensioned using a stock Fromm A480 tool and a Fromm A480 tool employinga low-friction insert. The stock tool produced bands tensioned to about508 lbf (Alloy 400) and 629 lbf (Zeron). The tool employing a lowfriction insert performed much better, tensioning bands to about 1196lbf (Alloy 400) and about 1301 lbf (Zeron). The standard deviation ofband tension was also reduced when using a modified tool by an order ofmagnitude, from 284 to 34 for Zeron and from 145 to 58 for Alloy 400.Use of a low-friction insert increased tension on average about 673 lbf(Zeron) and 688 lbf (Alloy 400) over existing inserts. Further, therepeatability in performance is desirable to operators as they cantension many bands without having to make adjustments to the toolconfiguration.

Further, embodiments of the present invention reduce galling instainless steel bands. In one test, 10,000 pulls were performed withoutfailure, i.e., tension wheel slippage. Also, the nature of thecontemplated low-friction insert allows it to be reversible (i.e.,removed, flipped over, and replaced), thereby doubling its life andlowers tension output, which reduces the risk of damage to the seal andband at higher pressure settings.

With reference now to FIGS. 10A-10E, modification of a stock tool isshown. Initially, side cover screws 18 are removed and the side cover 22is pried from the tool, which exposes the tension wheel 6 and insertscrew 26. The tension wheel 6 and insert 10 are then removed. Thereplacement insert 10 is then installed into the foot 14 of the tool anda tension wheel 6 is placed back on its axle 30. Minute changes can bemade to the gap between the tension wheel 6 and the insert 10. Finally,the side cover 22 and screws 18 are placed back on the tool and gapadjustment screws are used to further maintain a predetermined gapbetween the tension wheel 6 and the insert 10.

Although described numerous times herein, the aspects of the presentinvention are not limited to the Fromm A480 tool. That is, one of skillin the art will appreciate that tools of other manufacture and type canbe used without departing from the scope of the invention.

While various embodiments of the present invention have been describedin detail, it is apparent that modifications and alterations of thoseembodiments will occur to those skilled in the art. However, it is to beexpressly understood that such modifications and alterations are withinthe scope and spirit of the present invention, as set forth in thefollowing claims. Further, the invention(s) described herein is capableof other embodiments and of being practiced or of being carried out invarious ways. In addition, it is to be understood that the phraseologyand terminology used herein is for the purpose of description and shouldnot be regarded as limiting. The use of “including,” “comprising,” or“having” and variations thereof herein is meant to encompass the itemslisted thereafter and equivalents thereof as well as additional items.

What is claimed is:
 1. A band tensioning tool comprising: apneumatically-powered tension wheel; a foot spaced from said tensionwheel, said foot having a recess; a lever associated with said foot thatselectively moves said foot away from said tension wheel; and an insertpositioned in said insert, said recess being made of a low-frictionmaterial.
 2. The tool of claim 1, wherein said low-friction insert has aroom temperature tensile strength of between about 20,000 to 32,000 psi,room temperature tensile modulus of between about 3-4 Mpsi, roomtemperature flexural strength of between about 30,000 to 50,000 psi,room temperature flexural modulus of between about 4.9 to 4.12 Mpsi,room temperature compressive strength of between about 40,000-75,000psi, and room temperature coefficient of friction of between about 0.15to 0.20.
 3. The tool of claim 1, wherein said low friction insert has acoefficient of friction of between about 0.15 to 0.20.
 4. The tool ofclaim 1, wherein said low friction insert has a coefficient of frictionof between about 0.05 to 0.40.
 5. The tool of claim 1, wherein said lowfriction insert is made of a composition comprised of a mixture ofbetween about 40%-60% pmr-15 polyamide resin and between about 40%-60%of at least one of carbon fiber and graphite.
 6. The tool of claim 1,wherein said insert has a circular outer perimeter.
 7. A band tensioningtool comprising a gear housing having a tension wheel protruding from aportion thereof; a foot pivotally coupled to said gear housing andhaving a band support portion disposed generally opposite said tensionwheel; a compression foot spring having a first end portion associatedwith said gear housing and a second end portion associated with saidfoot, said compression foot spring adapted to pivotally bias said bandsupport portion of said foot toward the tension wheel; a handle having afirst end portion coupled to said foot, said handle having anintermediate portion and a second end portion extending from said footgenerally along the axial dimension of said gear housing, said handlebeing actuatable toward and away from said gear housing to pivot saidfoot against the pivotal bias of said compression foot spring, whichmoves said band support portion away from said tension wheel to providea band-receiving gap, the improvement comprising: a low-friction insertincorporated in said foot, said low-friction insert being generallyaligned with, but spaced from, said tension wheel when said handle isactuated toward said gear housing.
 8. The tool of claim 7, wherein saidlow-friction insert has a room temperature tensile strength of betweenabout 20,000 to 32,000 psi, room temperature tensile modulus of betweenabout 3-4 Mpsi, room temperature flexural strength of between about30,000 to 50,000 psi, room temperature flexural modulus of between about4.9 to 4.12 Mpsi, room temperature compressive strength of between about40,000-75,000 psi, and room temperature coefficient of friction ofbetween about 0.15 to 0.20.
 9. The tool of claim 7, wherein said lowfriction insert has a coefficient of friction of between about 0.05 to0.40.
 10. The tool of claim 7, wherein said low friction insert is madeof a composition comprised of a mixture of between about 40%-60% pmr-15polyamide resin and between about 40%-60% of at least one of carbonfiber and graphite.
 11. A method of securing a band about a plurality ofobjects, comprising: providing a band tensioning tool comprising apneumatically-powered tension wheel, a foot spaced from said tensionwheel, said foot having a recess, a lever associated with said foot thatselectively moves said foot away from said tension wheel, and an insertpositioned in said insert, said recess being made of a low-frictionmaterial; moving said lever to separate said foot from said tensionwheel; placing a band between said tension wheel and said foot;releasing said lever which moves said insert into engagement with saidband, said band also being engaged to said tension wheel; rotating saidtension wheel, which moves said band across said insert; achieving apredetermined band tension; deforming a seal about said band to create aband loop; and severing an excess portion of said band.
 12. The methodof claim 11, wherein said band does not substantially gall when it movesacross said insert.
 13. The method of claim 11, wherein said tool iscapable of tensioning bands made of at least one of a carbon steel, astainless steel alloy, and a steel/nickel alloy, wherein retained forceis between about 200-400 lbf. is achieved, regardless of band material.14. The method of claim 11, wherein said tool is capable of tensioningbands made of at least one of Zeron, Alloy 400, one-quarter hard 304stainless steel, and 316 stainless steel, wherein retained force isbetween about 200-400 lbf. is achieved, regardless of band material. 15.The method of claim 11, wherein said tool is capable of tensioning aplurality of Zeron bands with a standard deviation associated withapplied band tension is about 30-40.
 16. The method of claim 11, whereinsaid tool is capable of tensioning a plurality of Zeron bands such thata standard deviation associated with applied band tension is reduced byabout 80-90% with respect to a similar tool that does not employ alow-friction insert.
 17. The method of claim 11, wherein said tool iscapable of tensioning a plurality of Alloy 400 bands with a standarddeviation associated with applied band tension is about 50-60.
 18. Themethod of claim 11, wherein said tool is capable of tensioning aplurality of Alloy 400 bands such that a standard deviation associatedwith applied band tension is reduced by about 55-65% with respect to asimilar tool that does not employ a low-friction insert.
 19. A bandtensioned by the method of claim 11.